Ben's backstory when it's revealed that the guard he murdered to save his wife ultimately saved an entire vault including his unborn son because Vault Tec planned for that vault to have no medical personnel and his wife was a nurse.
The Ranger (aka James Eldridge) revealing that despite living to a grand old age in the Vault, his wife never remarried and died clutching her wedding ring. It's been passed down as a treasured heirloom in his family for over 200 years.
"Get our family out of here."
Twig sacrificing the universal processor for his Pip-Boy to allow the machinery in the Lockre to run again, allowing them to manufacture new weapons and ammunition to ensure that their peaceful community can remain free from slavers, raiders and especially the Legion.